Conical reducers are commonly used in HVAC ducting to serve as a transition between a larger diameter duct and a smaller diameter duct. The conical reducer can be joined between an end of a larger size diameter or duct and the adjacent end of a smaller diameter duct. Also, conical fittings can be used to intersect a larger diameter duct in a direction transversely to the length of the larger diameter duct. For this purpose, conical taps and saddle taps are typically used. Further, wye fittings can be used to connect two smaller diameter lines to the end of a larger diameter line, with the two smaller diameter lines being angularly disposed relative to each other.
Such conical fittings typically have been formed from a flat pattern that is then rolled to form a conical shape and welded along a seam. Collar sections are then welded, riveted or otherwise attached to the smaller end portion of the conical fitting, and also sometimes to the larger end portion of the conical fitting. This is a slow, labor intensive process causing the conical fittings to be relatively expensive to manufacture.
Moreover, current manufacturing techniques limit the gauge of material used to form the conical reducers to about 22 gauge. It would be advantageous if thinner gauge material, perhaps down to 26 gauge, could be used for conical fittings thereby reducing the weight and cost of such fittings. The present invention addresses the foregoing shortcomings of existing methods of manufacturing conical fittings by incorporating spin forming techniques.